The present invention relates to a cooler for transferring heat generated from a driver for card-typed storage medium as a component in a personal computer, a digital camera, and the like, to cool the storage medium, and a method for fabricating the cooler. The present invention also relates to an electronic apparatus such as a personal computer, and a digital camera, which is equipped with the cooler.
Since a compact and low-profile storage medium such as a memory stick (registered trademark), smart media (registered trademark), and a compact flash (registered trademark) as compared with conventional one such as a floppy (registered trademark) disks may have a large amount of storage capacity, the storage medium has been generically used in an electronic apparatus such as a personal computer, and a digital camera.
In such the storage medium, there are memories wherein a driver and a flash memory are integral parts, and wherein a driver is provided with a memory main body or another card-typed memory, for example. At any rate, this storage medium has recently had a considerable amount of storage capacity.
Such the considerable amount of storage capacity of the storage medium causes the driver to generate a great amount of heat, thereby resulting in a malfunction therein.
In order to avoid the malfunction, it is conceivable that a cooler will be provided with the electronic apparatus side wherein a technology using a heat pipe is used as cooling method.
The heat pipe is a metallic pipe having a wick structure on an inside wall thereof, maintained under vacuum, and filled with a small amount of water, alternatives for chlorofluorocarbons or the like. An end of the heat pipe is attached to heat source to be heated and a working fluid then evaporates or is vaporized in the heat pipe, whereby heat is acquired as latent heat (of evaporation). The vapor is moved toward a low-temperature portion thereof rapidly (almost at the velocity of sound) and it then turns back to a liquid condition by cooling of the low-temperature portion and extracts heat (liberated heat as latent heat when vapor condenses). The working fluid returns to its original position through the wick structure (or by gravity) so that heat transfer can be successively performed with efficiency.
Since the conventional heat pipe has a pipe shape and occupies a large space, it is unsuitable for a cooler for an electronic apparatus such as a personal computer, and a digital camera because the cooler is required to be downsized and low-profiled.
In order to downsize the heat pipe, a cooler has proposed such that silicon and glass board members each having grooves on their mating surfaces are connected together to form a passage between them as the heat pipe. Note that as connecting them, the passage is filled with a small amount of water, alternatives for chlorofluorocarbons or the like and sealed. Such the liquid changes in phase into and from the vapor inside the heat pipe, thereby serving as the heat pipe.
If, however, the heat pipe is formed using the silicon board member as described above, an object to be cooled diffuses too much heat because of high thermal conductivity of silicon itself. This causes inadequate or no evaporation of the working liquid inside the heat pipe, thereby failing to suitably deliver a performance of the heat pipe.
In order to improve the inconvenience, the inventors have proposed such a technology that a plastic board member having low thermal conductivity can be used instead of silicon board member, thereby preventing the heat from being improperly diffused at a surface of the board member to allow a performance of the heat pipe to improve.
In this case, however, it is difficult to transfer the heat from an object to be cooled into the working liquid inside the heat pipe because of low thermal conductivity of the plastic material itself, thereby resulting in inadequate evaporation of the working liquid inside the heat pipe. This may fails to suitably deliver a performance of the heat pipe.